Tapping sugar maple trees to obtain their sweet sap has been practiced for hundreds of years. Over time, techniques and equipment have evolved to better meet the needs of the growing maple industry. Spile design is no exception and has changed dramatically over the past 100 years. Despite these changes, current spile designs still present drawbacks in various areas.
Currently, 5/16 and 7/16 inches are common spile diameters that are used today. Canadian patent number CA2233739 to Chabot introduced the current industry standard 5/16 spile. Appropriate size holes are bored into the tree at the start of each sap season. A spile is inserted in each hole to transfer sap from the tree to the tubing. These size holes leave large wounds in the tree, which can take years to heal. Such wounds take energy away from the health and vigor of the tree, reduce growth rate (and basal area), and increase its susceptibility to pests and disease. Furthermore, stress can negatively impact the tree's productivity and consequently the profitability.
Plastic is the most prevalent material that modern spiles are made of. On a microscopic level, plastic is porous and cannot be adequately sterilized for re-use. Because of that, plastic spiles are typically disposed of after each season, which adds to increasingly high levels of virgin resource consumption and waste in landfills. Growing concern for sustainability and the environment encourages producers to seek alternative spile solutions.
Another issue with plastic spiles is that once installed, they are permanently attached to the tubing. In order to remove them at the end of the season, they must be cut off. This continually shortens tubing and can create the need to prematurely replace tubing lines. Prior art U.S. Pat. No. 6,438,895 to Fortier disclosed a spout feature that was partially removable. However, being partially removable was only a partial improvement over other prior art. The design was too complex and cumbersome to be practically applied, especially in large-scale operations. Furthermore, the design called for part of the spout to remain in the environment during the off-season. There it can be easily contaminated by bacteria or damaged by rodents.
Unlike stainless steel, plastic spiles are susceptible to damage from rodents via gnawing and chewing.
Some prior arts have attempted to address these limitations. However, none have been successful in addressing all of the issues while still maintaining the productivity and functionality of the spile. The U.S. patent number 2005/0000153A1 to White is one such undertaking of a small diameter spile. However, poor machining and insufficient length and radius severely impacts the performance of the spile. The head is poorly rounded, making it difficult to connect the tubing, thus slowing the connection process. For a large operation with thousands of spiles, this adds burdensome time and labor costs to every season.
Additionally, the length of the spile is too short to successfully tap old trees with thick bark. Large, mature trees can be high producers of maple sap and it is important that spile length be adequate for proper tubing attachment. This prior art has poor visibility. The grey color is easily camouflaged by bark colors. Difficulty in finding spiles can also lead to losses in time and money when every spile needs to be removed at the end of the season.
Finally, the most critical flaw with this prior art is leakage due to inadequate sealing surfaces. Leaks are the bane of any maple operation and take time, effort, and money to repair.
Although prior art innovations in spile design have achieved various performance objectives, none have been able to fully embody the qualities of an ideal spile. A need still exists for a reusable small diameter spile that can perform effectively in the field and meet the requirements of both small and large producers.
The invention imparted herein offers solutions to problems presented by the prior arts and fulfills the need for a long lasting, high performance small diameter spile.